infer_levene_test {inferr}

Levene's test for equality of variances

Description

infer_levene_test reports Levene's robust test statistic for the equality of variances and the two statistics proposed by Brown and Forsythe that replace the mean in Levene's formula with alternative location estimators. The first alternative replaces the mean with the median. The second alternative replaces the mean with the 10

Usage

infer_levene_test(data, ...)

## Default S3 method:
infer_levene_test(data, ..., group_var = NULL, trim_mean = 0.1)

Arguments

data

a data.frame or tibble

...

numeric; columns in data

group_var

factor; column in data

trim_mean

trimmed mean

Value

infer_levene_test returns an object of class "infer_levene_test". An object of class "infer_levene_test" is a list containing the following components:

bf

Brown and Forsythe f statistic

p_bf

p-value for Brown and Forsythe f statistic

lev

Levene's f statistic

p_lev

p-value for Levene's f statistic

bft

Brown and Forsythe f statistic using trimmed mean

p_bft

p-value for Brown and Forsythe f statistic using trimmed mean

avgs

mean for each level of the grouping variable

sds

standard deviations for each level of the grouping variable

avg

combined mean

sd

combined standard deviation

n

number of observations

n_df

numerator degrees of freedom

d_df

denominator degrees of freedom

levs

levels of the grouping variable

lens

number of observations for each level of the grouping variable

type

alternative hypothesis

Deprecated Function

levene_test() has been deprecated. Instead use infer_levene_test().

References

Bland, M. 2000. An Introduction to Medical Statistics. 3rd ed. Oxford: Oxford University Press.

Brown, M. B., and A. B. Forsythe. 1974. Robust tests for the equality of variances. Journal of the American Statistical Association 69: 364–367.

Carroll, R. J., and H. Schneider. 1985. A note on Levene’s tests for equality of variances. Statistics and Probability Letters 3: 191–194.

Examples

# using grouping variable
infer_levene_test(hsb, read, group_var = race)

# using  variables
infer_levene_test(hsb, read, write, socst)